Viruses are data which is compiled or inserted in an application program for destroying system functions, will affect the normal use of the application program, are able to self-replicate, and generally take the form of a set of instructions or program codes. Viruses, also called computer viruses, may comprise but are not limited to Trojans, backdoors, local area network worms, mail worms, spyware, infective viruses or Rootkits/Bootkits, which have the characteristics of destruction, replication and infection.
However, in some cases, for example, where antivirus software has a limited monitoring capability, or there are various viruses and they show rapid growth, it is hard to detect malicious process behaviors caused by viruses after running in time.